Device and method for measuring torque of a rotating shaft

Abstract

The invention relates to a device (V) for measuring the torque (M) of a rotating shaft (W, W'); which device (V) comprises a measuring body (1, 1') and an evaluation unit (2); which measuring body (1, 1') is attachable to the shaft (W, W') and, in the attached state, rotates with the shaft (W, W') about a longitudinal axis (A) of the shaft (W, W'); which measuring body (1, 1') comprises a measuring unit (12), a measuring amplifier unit (13), and a telemetry unit (14); which measuring unit (12), in the attached state, generates a measurement signal (MS) under the influence of the torque (M); which measuring amplifier unit (13) amplifies the measurement signal (MS); which telemetry unit (14) digitizes the amplified measurement signal (MS) and transmits it wirelessly to the evaluation unit (2); wherein the measuring body (1, 1') has a principal axis of inertia (X) which principal axis of inertia (X) lies on the longitudinal axis (A) in the fixed state.

Description

Technical field

[0001] The invention relates to a device and a method for measuring the torque of a rotating shaft according to the preambles of the independent claims. State of the art

[0002] A shaft is a machine element that rotates around an axis and whose function is to transmit rotary motion and torque during rotation. Such a shaft has diverse applications in machines, for example, in automotive engineering as a drive shaft, in energy technology as a turbine shaft, etc.

[0003] The torque transmitted by the shaft allows for the determination of important machine parameters such as power, efficiency, friction coefficients, etc. For this reason, torque is measured both during machine development and in industrial applications.

[0004] A device for measuring the torque of a rotating shaft is known from German patent application DE 19719921A1. This device comprises a measuring element in the form of a measuring flange that rotates with the shaft and an evaluation unit. The evaluation unit has a stator antenna. The evaluation unit is spatially separated from the shaft and the measuring element. The measuring element, in turn, has a strain gauge, a measuring amplifier, and a telemetry device with a rotor antenna. Under the influence of the torque to be measured, the strain gauge generates a measurement signal. The measuring amplifier amplifies the measurement signal, and the telemetry device digitizes the amplified measurement signal into measurement data and transmits the measurement data via the rotor antenna to the stator antenna, from where the measurement data is sent to the evaluation unit. Parameters of the measuring amplifier, such as the zero point or the gain factor, can be adjusted via signals sent from the stator antenna to the rotor antenna.

[0005] Users now want to use the device for shafts with different diameters. Therefore, several measuring elements are provided, their dimensions adapted to the respective shaft diameters, while the evaluation unit remains the same. The differently sized measuring elements affect the measurement accuracy, especially with rapidly rotating shafts at speeds well over 1000 min⁻¹, which is why the measurement signals generated for different shaft diameters are only partially comparable.

[0006] A first object of the present invention is to improve the device for measuring the torque of a rotating shaft known from DE19719921A1. This is intended to increase the measurement accuracy. The invention then further aims to provide a method that enables a simple, rapid, and cost-effective measurement of the torque of a rotating shaft. Description of the invention

[0007] These tasks are solved by the characteristics of independent claims.

[0008] The invention relates to a device for measuring the torque of a rotating shaft; which device comprises a measuring body and an evaluation unit; which measuring body is attachable to the shaft and, in the attached state, rotates with the shaft about a longitudinal axis of the shaft; which measuring body comprises a measuring unit, a measuring amplifier unit, and a telemetry unit; which measuring unit, in the attached state, generates a measurement signal under the influence of the torque; which measuring amplifier unit amplifies the measurement signal; which telemetry unit digitizes the amplified measurement signal and transmits it wirelessly to the evaluation unit; wherein the measuring body has a principal axis of inertia, which principal axis of inertia lies on the longitudinal axis in the attached state.

[0009] The invention also relates to a method for measuring the torque of a rotating shaft; using a device with a measuring body and an evaluation unit; the measuring body comprising a measuring unit, a measuring amplifier unit, and a telemetry unit; wherein the measuring body is attached to the shaft; wherein the shaft is set into rotation about a longitudinal axis of the shaft and transmits the torque; wherein the measuring unit generates a measurement signal under the influence of the torque; wherein the measuring amplifier unit amplifies the measurement signal; wherein the telemetry unit digitizes the amplified measurement signal and transmits it wirelessly to the evaluation unit; and wherein a measuring body is provided, the measuring body having a principal axis of inertia which, in the attached state, lies on the longitudinal axis.

[0010] The invention is based on the finding that the measuring element of the device known from DE19719921A1 for measuring the torque of a rotating shaft has a heterogeneous composition, as it consists of a measuring flange, a strain gauge, a measuring amplifier, and a telemetry device with a rotor antenna. Due to this heterogeneous composition, its mass distribution with respect to the longitudinal axis of the rotating shaft is also asymmetrical, with the result that the center of gravity of the measuring element is not located on the longitudinal axis, leading to a static imbalance, or that the principal axis of inertia of the measuring element is tilted at an angle ≠0° to the longitudinal axis, leading to a dynamic imbalance. The imbalance resulting from the static and dynamic imbalances causes a disturbance torque, which is superimposed on the torque to be measured and distorts the torque measurement.The measuring body of the device according to the invention is statically and dynamically balanced and the interfering torque is minimized, which increases the measuring accuracy of the device.

[0011] Advantageous further developments of the invention are listed in the dependent claims. Brief description of the drawings

[0012] The invention will now be explained in more detail using the figures as an example. They show Fig. 1 a schematic representation of the device V for measuring the torque M of a shaft W, W' with a measuring body 1, 1' and an evaluation unit 2; Fig. 2 a view of part of a first embodiment of the measuring body 1 and the shaft W according to Fig. 1 ; Fig. 3 a view of part of a second embodiment of the measuring body 1' and the shaft W' according to Fig. 1 ; Fig. 4 a view of part of the measuring body 1, 1' according to Fig. 1with a measuring unit 12 between a first measuring body housing 11a and a second measuring body housing 11b; Fig. 5 an exploded view of the measuring body 1, 1' according to Fig. 1 with a measuring amplifier unit 13 and a telemetry unit 14 in the first measuring body housing 11a and with an energy storage unit 15 in the second measuring body housing 11b; Fig. 6 a view in a first cross-section BB along a first sectioning axis B through the first measuring body housing 11a according to Fig. 5 ; and Fig. 7. a view in a second cross-section CC along a second sectioning axis C through the second measuring body part housing 11b according to Fig. 5 .

[0013] The same reference symbols denote the same objects in the figures. Ways to implement the invention

[0014] Fig. 1Figure 1 shows a shaft W, W' which can rotate about a longitudinal axis A of the shaft W, W' and transmits a torque M during rotation. The shaft W, W' is a rotationally symmetric body with respect to the longitudinal axis A and is made of a mechanically resistant material such as metal, plastic, etc.

[0015] Furthermore, it shows Fig. 1 A device V for measuring the torque M of the shaft W, W'. The device V comprises a measuring body 1, 1' and an evaluation unit 2. The measuring body 1, 1' is attached to the shaft W, W' and rotates with the shaft W, W' about the longitudinal axis A. The evaluation unit 2 is spatially spaced apart from the shaft W, W' and from the measuring body 1, 1'.

[0016] In the views according to Figs. 1 to 4 and the exploded view according to Fig. 5The measuring body 1, 1' is hollow cylindrical. In the region of the longitudinal axis A, the measuring body 1, 1' has an axial cavity 10, 10'. The axial cavity 10, 10' has a cavity diameter D10, D10'. The cavity diameter D10, D10' is dimensioned such that it is equal to the shaft diameter DW, DW' in the radial direction perpendicular to the longitudinal axis A. With respect to the longitudinal axis A, the measuring body 1, 1' is attached radially to the outside of the shaft W, W'. Preferably, the attachment is achieved by positive locking and frictional clamping. The attachment is reversibly detachable.

[0017] Now, the shafts W and W' can have different shaft diameters WD and WD'. Accordingly, the device has several measuring bodies 1 and 1' whose cavity diameters D1 and D1' are equal to the different shaft diameters DW and DW'. The following are shown. Figs. 2 and 3Two embodiments of the shaft W, W' and the axial cavity 10, 10' of the measuring body 1, 1'. In the first embodiment according to Fig. 2 The shaft W has a shaft diameter DW of 25 mm, while the shaft W' in the second embodiment according to Fig. 3 has a shaft diameter DW' of 45 mm. In a first embodiment according to Fig. 2 The measuring body 1 has a cavity diameter D10 of 25 mm, while the measuring body 1' of the second embodiment according to Fig. 3 has a cavity diameter D10' of 45 mm. Of course, it is possible for those skilled in the art to implement the invention with shafts and axial cavities with diameters smaller than 25 mm and shafts and axial cavities with diameters larger than 45 mm.

[0018] The measuring body 1, 1' comprises a measuring body housing 11, a measuring unit 12, a measuring amplifier unit 13, a telemetry unit 14 and an energy storage unit 15.

[0019] The measuring body housing 11 is designed to protect the measuring unit 12, the measuring amplifier unit 13, the telemetry unit 14 and the energy storage unit 15 from harmful environmental influences such as dust, moisture, etc.

[0020] In the view according to Fig. 4 and the exploded view according to Fig. 5 The measuring body housing 11 is multi-part and has a first measuring body part housing 11a and a second measuring body part housing 11b; it has a first measuring body part closure 11aa and a second measuring body part closure 11bb.

[0021] Preferably, the measuring body housing 11 is bisected in a plane lying along the longitudinal axis A, and the two measuring body part housings 11a, 11b have the shape of congruent halves of hollow cylinders, and the two measuring body part closures 11aa, 11bb have the shape of halves of end faces of hollow cylinders. In the region of the longitudinal axis A, each of the two measuring body part housings 11a, 11b is bounded by the axial cavity 10, 10'. The two measuring body part housings 11a, 11b and the two measuring body part closures 11aa, 11bb are made of a mechanically resistant material such as metal, plastic, etc.

[0022] The first measuring element housing 11a has at least one first housing cavity 110a, 110a'. The first measuring element closure 11aa is designed to seal the first housing cavity 110a, 110a' tightly against dust and moisture. The second measuring element housing 11b has at least one second housing cavity 110b, 110b'. The second measuring element closure 11bb is designed to seal the second housing cavity 110b, 110b' against dust and moisture. Preferably, the closure of the first and second housing cavities 110a, 110a', 110b, 110b' is a combination of a positive fit and a friction fit, such as a screw connection.

[0023] In the exploded view according to Fig. 5 The first housing cavity 110a, 110a' accommodates the measuring amplifier unit 13 and the telemetry unit 14, and the second housing cavity 110b, 110b' accommodates the energy storage unit 15.

[0024] The first measuring body housing 11a, equipped with the measuring amplifier unit 13 and the telemetry unit 14 in the first housing cavity 110a, 110a' and closed with the first measuring body part closure 11a, is hereinafter also referred to as the first measuring body part 1a. Accordingly, the second measuring body housing 11b, equipped with the energy storage unit 15 in the second housing cavity 110b, 110b' and closed with the second measuring body part closure 11b, is hereinafter also referred to as the second measuring body part 1b.

[0025] Preferably, the two measuring body part housings 11a, 11b have a joint unit 111 and a connecting unit 112.

[0026] The joint unit 111 is designed to pivotally hold the two measuring body housings 11a, 11b together about the longitudinal axis A. (See exploded view according to...) Fig. 5The joint unit 111 is a hinge with at least one pin 111a and several bushings 111b. The joint unit 111 holds the two measuring body housings 11a, 11b together on one side. By pivoting about the longitudinal axis A, the two measuring body housings 11a, 11b can be reversibly moved from an open state to a closed state and are held together by the joint unit 111.

[0027] The connecting unit 112 is designed to detachably connect the two measuring body housings 11a and 11b. Preferably, the connecting unit 112 is a combination of a positive fit and a friction fit, such as a screw connection, a plug connection, etc. (See view according to...) Fig. 4 and the exploded view according to Fig. 5The connecting unit 112 consists of at least one screw 112a and at least one through-hole 112aa in the first measuring body housing 11a, and at least one threaded bore 112b in the second measuring body housing 11b. The head of the screw 112a is held in the through-hole 112aa, and a thread of the screw 112a protrudes through the through-hole 112aa and can be connected to the threaded bore 112b. Only after the connecting unit 112 has been loosened can the two measuring body housings 11a and 11b be pivoted about the longitudinal axis A. Loosening the connecting unit 112 is also reversible.

[0028] In the views according to Figs. 2 and 3 The two measuring body housings 11a, 11b are in the closed position and are held together on one side by the joint unit 111 and connected to each other on the other side via the connecting unit 112. In the view according to Fig. 4The connecting unit 112 is detached and the two measuring body part housings 11a, 11b are in the open state by pivoting about the longitudinal axis A and are only held together on one side by the joint unit 111.

[0029] In the folded state, the two measuring body parts 1a, 1b are balanced, i.e., a center of gravity S of the measuring body 1, 1' lies on the longitudinal axis A and also a principal axis of inertia X of the measuring body 1, 1' lies on the longitudinal axis A and runs at an angle of 0° untilted to the longitudinal axis A.

[0030] There are few degrees of freedom for balancing, because the external dimensions and weight of the measuring amplifier unit 13 and the telemetry unit 14 in the first measuring body housing 11a are predetermined, as are the external dimensions and weight of the energy storage unit 15 in the second measuring body housing 11b. The shaft diameter DW, DW' is also predetermined, and thus so is the cavity diameter D10, D10' of the axial cavity 10, 10'.

[0031] Thus, the remaining degrees of freedom for balancing are the weight and weight distribution of each of the two measuring body housings 11a, 11b. The weight and weight distribution of the first measuring body housing 11a and the second measuring body housing 11b are adjusted for balancing such that the two measuring body parts 1a, 1b are balanced in the closed state.

[0032] To illustrate this, show Fig. 6a view in a first cross-section BB along a first cutting axis B through the first measuring body part housing 11a according to Fig. 5 and Fig. 7 shows a view in a second cross-section CC along a second section axis C through the second measuring body part housing 11b according to Fig. 5 .

[0033] In the view according to Fig. 6The first housing cavity 110a, 110a' consists of a first oblong cavity 110a for receiving the measuring amplifier unit 13 and a further first oblong cavity 110a' for receiving the telemetry unit 14. The first oblong cavity 110a is bounded on the outside of the first measuring body housing 11a by a first edge 110aa. Inside, the first oblong cavity 110a has at least one first undercut 110aaa, shown as a dotted line. The further first oblong cavity 110a' is bounded on the outside of the first measuring body housing 11a by another first edge 110aa'. Inside, the further first oblong cavity 110a' has at least one further first undercut 110aaa', shown as a dotted line. The first undercut 110aaa and the further first undercut 110aaa' are hereinafter also referred to as first undercut 110aaa, 110aaa'.The size and shape of the first undercut 110aaa, 110aaa' are used to adjust the weight and weight distribution of the first measuring body part housing 11a so that the principal axis of inertia X of the measuring body 1, 1' lies on the longitudinal axis A when fixed.

[0034] In the view according to Fig. 7The second housing cavity 110b, 110b' consists of a first kidney-shaped cavity 110b for accommodating two first lithium-ion batteries of the energy storage unit 15 and a further first kidney-shaped cavity 110b' for accommodating two further lithium-ion batteries of the energy storage unit 15. The second kidney-shaped housing cavity 110b is bounded on the outside of the second measuring body housing 11b by a second edge 110bb. Inside, the second kidney-shaped housing cavity 110b has at least one second undercut 110bbb, shown as a dotted line. The further second kidney-shaped housing cavity 110b' is bounded on the outside of the second measuring body housing 11b by a further second edge 110bb'. Inside, the further second kidney-shaped housing cavity 110b' has at least one further second undercut 110bbb' shown with dotted lines.The second undercut 110bbb and the further second undercut 110bbb' are hereinafter also referred to as second undercut 110bbb, 110bbb'. The size and shape of the second undercut 110bbb, 110bbb' are used to adjust the weight and weight distribution of the second measuring body housing 11b such that the principal axis of inertia X of the measuring body 1, 1' lies on the longitudinal axis A when mounted.

[0035] Through balancing, the two measuring body parts 1a and 1b are matched to each other with respect to weight and weight distribution. The two balanced measuring body parts 1a and 1b have the same weight and the same weight distribution.

[0036] The accuracy of the balancing is specified according to the standard DIN ISO 1940-1 using a balancing grade. Preferably, the balancing grade of the measuring body 1, 1' is less than or equal to 10, preferably less than or equal to 5.

[0037] Balancing minimizes the disturbance torque caused by static and dynamic imbalances, thus increasing measurement accuracy. Furthermore, the minimization of disturbance torque achieved through balancing normalizes the measurement signals. This makes measurement signals from measuring bodies 1, 1' with different cavity diameters D10, D10' comparable, because in all these measuring bodies 1, 1', the center of gravity S of the measuring body 1, 1' lies on the longitudinal axis A, and the principal axis of inertia X of the measuring body 1, 1' also lies on the longitudinal axis A.

[0038] Preferably, the first housing cavity 110a, 110a' in the first measuring body housing 11a is additively manufactured, as this is the only way to produce the first undercut 110aaa, 110aaa' with the preferred balancing quality. Preferably, the second housing cavity 110b, 110b' in the second measuring body housing 11b is also additively manufactured, as this is the only way to produce the second undercut 110bbb, 110bbb' with the preferred balancing quality.

[0039] The measuring unit 12 comprises a carrier unit 121, a strain gauge 122 and an electrical contact element 123.

[0040] The support unit 121 is hollow cylindrical. In the view according to Fig. 4 and the exploded view according to Fig. 5The support unit 121 is multi-part. Preferably, the support unit 121 is bisected in a plane lying in the longitudinal axis A into two support elements 121a, 121b, and the two support elements 121a, 121b have the shape of congruent halves of hollow cylinders. The two support elements 121a, 121b are made of a mechanically resistant material such as metal, plastic, etc.

[0041] The two support elements 121a, 121c have plug-in elements 121c such as snap hooks, etc. The plug-in elements 123c are attached at the ends of the two support elements 121a, 121b. The plug-in elements 121c are designed to form a detachable connection with each other by means of a positive locking mechanism.

[0042] The carrier unit 121 is designed to support the strain gauge 122 and the contact element 123. The carrier unit 121 supports the strain gauge 122 on an inner surface facing radially towards the shaft W, W'.

[0043] The strain gauge 122 is configured to generate a measurement signal MS under the influence of a torque M. The strain gauge 122 can be a full bridge, half bridge, or quarter bridge. Preferably, the strain gauge 122 generates the measurement signal MS with a bandwidth of 5 kHz. The measurement signal MS is an electrical voltage. The strain gauge 122 is electrically connected to the electrical contact element 123 via electrical conductors. The electrical conductors carry the measurement signal MS to the electrical contact element 123.

[0044] The electrical contact element 123 is designed to conduct the measuring signal MS through the carrier element 121 to an outer surface facing radially away from the shaft W, W'.

[0045] In the view according to Fig. 4 The measuring body 1, 1' is in the unfolded state. In the views according to Figs. 2 and 3The measuring body 1, 1' is in the closed state. In the closed state of the measuring body 1, 1', the electrical contact element 123 and the measuring amplifier unit 13 are configured to be electrically connected to each other via electrical contacts. The electrical contacts transmit the measurement signal MS to the measuring amplifier unit 13.

[0046] The measuring amplifier unit 13 comprises an electrical amplifier circuit 131 with an operational amplifier. The electrical amplifier circuit 131 is designed to amplify the measurement signal MS. The amplified measurement signal MS is also an electrical voltage. The electrical amplifier circuit 131 amplifies the measurement signal MS with adjustable gain factors of 10⁻¹, 10⁻², 10⁻³, 10⁻⁴, etc. The measuring amplifier unit 13 is electrically connected to the telemetry unit 14 via electrical conductors. The electrical conductors transmit the amplified measurement signal MS to the telemetry unit 14. The electrical conductors also transmit control data SD to the measuring amplifier unit 13.

[0047] The telemetry unit 14 has an electrical telemetry circuit 141 and a rotor antenna 142.

[0048] The electrical telemetry circuit 141 includes an analog-to-digital converter and is designed to digitize the amplified measurement signal MS into measurement data MD. The measurement data MD are binary number sequences with a preferably 16-bit resolution.

[0049] The rotor antenna 142 is configured to wirelessly transmit measurement data MD to the evaluation unit 2. For this purpose, the evaluation unit 2 has a stator antenna 20. The stator antenna 20 is configured to receive measurement data MD transmitted by the rotor antenna 142. The wireless data transmission between the rotor antenna 142 and the stator antenna 20 is bidirectional. The stator antenna 20 can send control data SD to the rotor antenna 142, and the rotor antenna 142 can receive control data SD transmitted by the stator antenna 20. In this wireless transmission, measurement data MD and control data SD are sent and received as electromagnetic waves. Preferably, the rotor antenna 142 and the stator antenna 20 transmit measurement data MD and control data SD wirelessly in the Industrial Scientific and Medical (ISM) band from 2.402 GHz to 2.480 GHz. The wireless transmission of the measurement data MD and the control data SD is Fig. 1 represented as curved circular segments.

[0050] The stator antenna 20 is electrically connected to the evaluation unit 2 via an electrical data line 21. The electrical data line 21 transmits measurement data MD to the evaluation unit 2 and it transmits control data SD to the stator antenna 20.

[0051] The energy storage unit 15 comprises at least one storage device for electrical energy, such as a rechargeable battery, a non-rechargeable battery, etc. Preferably, the energy storage unit 15 is a lithium-ion battery, a lithium-polymer battery, a zinc-air battery, etc. The energy storage unit 15 is designed to supply the measuring body 1, 1' with electrical energy for an operating time of at least 40 hours. The energy storage unit 15 is small and lightweight. (See exploded view according to...) Fig. 5The energy storage unit 15 features four lithium-ion batteries as storage, each with a capacity of 715mAh, a weight of 20g each, and external dimensions of 49mm in length and 14mm in diameter.

[0052] The energy storage unit 15 has an energy supply element 151. In the closed state of the measuring body 1, 1', the energy supply element 151, the measuring amplifier unit 13, and the telemetry unit 14 are configured to be electrically connected to one another via electrical contacts. Through these electrical contacts, the measuring amplifier unit 13 and the telemetry unit 14 in the first measuring body housing 11a are supplied with electrical energy by the energy storage unit 15 in the second measuring body housing 11b.

[0053] The energy storage unit 15 also has a power supply connector 152. The power supply connector 152 is a connector such as USB-C, etc. In the view according to Fig. 4and the exploded view according to Fig. 5The power supply connection 152 is located in the first measuring body housing 11aa. The power supply connection 152 is electrically connected to the measuring amplifier unit 13 in the first measuring body housing 11a. When the measuring body 1, 1' is closed, the power supply connection 152 is thus electrically connected via the measuring amplifier unit 13 to the energy supply element 151 and the energy storage unit 15 in the second measuring body housing 11b. The energy storage unit 15 can be charged with electrical energy by connecting an external electrical power supply via a cable to the power supply connection 152. Charging the measuring body 1, 1', which is attached to the shaft W, W', is quick and easy. The measuring body 1, 1' does not need to be removed from the shaft W, W' for this purpose. The empty energy storage unit 15 is charged to at least 80% of its capacity in a charging time of less than 30 minutes.

[0054] Furthermore, the energy storage unit 15 of the measuring body 1, 1' attached to the shaft W, W' can be replaced easily and quickly. The measuring body 1, 1' does not need to be removed from the shaft W, W' for this purpose either. By opening the second measuring body part closure 11bb, the second housing cavity 110b, 110b' is accessible from outside the measuring body 1, 1'. The energy storage unit 15 can then be removed from the second housing cavity 110b, 110b'. A new energy storage unit 15' can then be inserted into the second housing cavity 110b, 110b' to replace the removed energy storage unit 15. This allows the [missing information] shown in the exploded view to be [missing information]. Fig. 5The four lithium-ion batteries shown as storage units are replaced with fully charged lithium-ion batteries if they are empty. The second housing cavity 110b, 110b' is then closed again by the second measuring body part closure 11bb. The replacement of the energy storage unit 15 takes less than 5 minutes.

[0055] The evaluation unit 2 has at least one data storage 22, at least one data processor 23, at least one input / receive unit 24 and at least one output unit 25.

[0056] The evaluation unit 2 is designed to evaluate the measurement data MD and to generate control data SD for controlling the measuring body 1, 1'.

[0057] In the evaluation unit 2, an evaluation program P is stored in the data memory 22 and can be loaded into the data processor 23. The evaluation program P loaded into the data processor 23 generates instructions which are executed automatically by the evaluation unit 2. For the purposes of the invention, the adjective "automatic" means that the instructions generated by the evaluation program P are executed by the evaluation unit 2 without human intervention.

[0058] The evaluation unit 2 can be operated via the input / receiver unit 24. For the purposes of this invention, the verb "operate" means that a person can issue commands via the input / receiver unit 24, which commands are then executed by the evaluation unit 2. The input / receiver unit 24 can be a keyboard for entering commands, an antenna for receiving commands, etc. Commands are entered as character strings via the keyboard, and the evaluation unit 2 generates control data SD for them. Commands are received as electromagnetic waves via the antenna, and the evaluation unit 2 generates control data SD for them.

[0059] Thus, the evaluation unit 2 generates control data SD for controlling the measuring body 1, 1' on command from the evaluation program P or on command from the input / receive unit 24. The control data SD executes a variety of commands.

[0060] The measuring body 1, 1' can be started or stopped using the control data SD. For this purpose, the evaluation unit 2 generates control data SD containing information for starting or stopping the measuring body 1, 1' and transmits it to the measuring amplifier unit 13. The measuring amplifier unit 13 then starts or stops the measuring body 1, 1' according to the control data SD.

[0061] The zero point of the electrical amplifier circuit 131 can also be set using the control data SD. The zero point can drift over time and due to external influences such as temperature. Therefore, zero point adjustment is necessary for high measurement accuracy. The zero point should not deviate from the actual zero point by more than 10% (upper and lower limits). If the zero point is not within these limits, the evaluation program P determines a new zero point that lies within the limits. Alternatively, the input / receiver unit 24 issues a command to set a new zero point. The evaluation unit 2 then generates control data SD specifying the new zero point and transmits this control data SD to the measuring amplifier unit 13. The electrical amplifier circuit 131 then uses the new zero point according to the control data SD.

[0062] The gain factor of the electrical amplifier circuit 131 can also be set using the control data SD. Each amplified measurement signal MS can be displayed up to a maximum value or full scale. For optimal display, the amplified measurement signal MS should not exceed the full scale (upper limit) and should also not be more than one order of magnitude smaller than the full scale (lower limit). If the amplified measurement signal MS is not within these limits, the evaluation program P determines a different gain factor that brings the amplified measurement signal MS within the limits. Alternatively, the input / receiver unit 24 issues a command to set such a different gain factor. The evaluation unit 2 then generates control data SD specifying the gain factor and transmits this control data SD to the measurement amplifier unit 13.The electrical amplifier circuit 131 amplifies the measurement signal MS according to the control data SD.

[0063] Optionally, the device V includes a rotary angle sensor 30. The rotary angle sensor 30 can be an optical sensor, a magnetic sensor, etc., which non-contactly detects the rotation angle α of the shaft W, W' and generates a rotation angle signal WS for the detected rotation angle α. The rotary angle sensor 30 is electrically connected to the evaluation unit 2 via an electrical signal line 31. The electrical signal line 31 transmits an angle signal WS to the evaluation unit 2.

[0064] The evaluation unit 2 is designed to evaluate the angle signal WS. The evaluation program P, loaded into the data processor 23, derives information about the direction of rotation of shaft W, W' and the angular position of shaft W, W' from the angle signal WS.

[0065] The measuring body 1, 1' is attached to the shaft W, W' in three steps.

[0066] In a first step, the two support elements 121a, 121b are placed on the shaft W, W' and connected to each other via the plug-in elements 121.

[0067] In a second step, the two measuring body housings 11a, 11b are placed on the carrier unit 121 in the unfolded state.

[0068] In a third step, the two measuring body housings 11a, 11b are folded together by pivoting them about the longitudinal axis A and connected to each other via the connecting unit 112. When the measuring body 1, 1' is folded, the electrical contact element 123 and the measuring amplifier unit 13 are electrically connected to each other via electrical contacts. When the measuring body 1, 1' is folded, the energy supply element 151, the measuring amplifier unit 13, and the telemetry unit 14 are also electrically connected to each other via electrical contacts, and the measuring amplifier unit 13 and the telemetry unit 14 in the first measuring body housing 11a are supplied with electrical energy by the energy storage unit 15 in the second measuring body housing 11b. Reference symbol list

[0069] α Rotation angle A Longitudinal axis Burst Cutting axis B Burst cross-section C Second cutting axis C Second cross-section D10, D10' Cavity diameter M Torque MD Measurement data MS Measurement signal P Evaluation program S Center of gravity SD Control data V Device W, W' Shaft WD, WD' Shaft diameter WS Angle signal X Inertia 1, 1' Measuring body 1a, 1b' Measuring body part 10, 10' Axial cavity 11 Measuring body housing 11a, 11b Measuring body part housing 11aa, 11bb Measuring body part closure 110a, 110a' First housing cavity 110aa, 110aa' First edge 110aaa, 110aaa' First undercut 110b, 110b' Second housing cavity 110bb, 110bb'second edge 110bbb, 110bbb'second undercut 111joint unit 111apin 111bbush 112connecting unit 112ascrew 112aathrough hole 112bthreaded hole 12measuring unit 121carrier unit 121a,121b Carrier element 121c Plug-in element 122 Strain gauge 123 Electrical contact element 13 Measuring amplifier unit 131 Electrical amplifier circuit 14 Telemetry unit 141 Electrical telemetry circuit 142 Rotor antenna 15, 15' Energy storage unit 151 Energy supply element 152 Power supply connection 20 Stator antenna 21 Electrical data line 2 Evaluation unit 22 Data storage 23 Data processor 24 Input / receive unit 25 Output unit 30 Rotary angle sensor 31 Electrical signal line

Claims

1. Device (V) for measuring the torque (M) of a rotating shaft (W, W'); which device (V) has a measuring body (1, 1') and an evaluation unit (2); which measuring body (1, 1') can be fastened to the shaft (W, W') and, in the fastened state, rotates with the shaft (W, W') about a longitudinal axis (A) of the shaft (W, W'); which measuring body (1, 1') has a measuring unit (12), a measuring amplifier unit (13), and a telemetry unit (14); which measuring unit (12), in the fastened state, generates a measuring signal (MS) under the effect of the torque (M); which measuring amplifier unit (13) amplifies the measuring signal (MS); which telemetry unit (14) digitizes the amplified measuring signal (MS) and transmits it wirelessly to the evaluation unit (2); characterized in that the measuring body (1, 1') has a main axis of inertia (X), which main axis of inertia (X) lies on the longitudinal axis (A) in the attached state.

2. Device (V) according to claim 1, characterized in thatthe measuring body (1, 1') has a measuring body housing (11), which measuring body housing (11) is multi-part and has a first measuring body part housing (11a) with a first housing cavity (110a, 110a'); and that the first housing cavity (110a, 110a') accommodates the measuring amplifier unit (13) and the telemetry unit (14).

3. Device (V) according to claim 2, characterized in that the measuring body housing (11) has a second measuring body part housing (11b) with a second housing cavity (110b, 11b'); that the measuring body (1, 1') has an energy storage unit (15); and that the second housing cavity (110b, 110b') accommodates the energy storage unit (15).

4. Device (V) according to claim 3, characterized in thatthe measuring body housing (11) has a second measuring body part closure (11b), which second measuring body part closure (11b) closes the second housing cavity (110b) with the energy storage unit (15); that the second measuring body part closure (11b) can be opened in the fastened state and the second housing cavity (110b, 110b') with the energy storage unit (15) is accessible from outside the measuring body (1, 1'); that the energy storage unit (15) can be removed from the second housing cavity (110b, 110b') and a new energy storage unit (15') can be inserted into the second housing cavity (110b, 110b'); and that the second housing cavity (110b, 110b') with the new energy storage unit (15') can be closed with the second measuring body part closure (11b).

5. Device (V) according to one of claims 3 or 4, characterized in thatthe first housing cavity (110a, 110a') has at least one first undercut (110aaa, 110aaa'); the weight and weight distribution of the first measuring body part housing (11a) are adjusted via the size and shape of the first undercut (110aaa, 110aaa') such that the main axis of inertia (X) of the measuring body (1, 1') lies on the longitudinal axis (A) in the fastened state; the second housing cavity (110b, 110b') has at least one second undercut (110bbb, 110bbb'); and that the weight and weight distribution of the second measuring body part housing (11b) are adjusted via the size and shape of the second undercut (110bbb, 111bbb') such that the main axis of inertia (X) of the measuring body (1, 1') lies on the longitudinal axis (A) in the fastened state.

6. Device (V) according to one of claims 3 to 5, characterized in that the two measuring body housings (11a, 11b) have the shape of congruent halves of hollow cylinders.

7. Device (V) according to one of claims 3 to 6, characterized in that the two measuring body housings (11a, 11b) are additively manufactured.

8. Device (V) according to one of claims 1 to 7, characterized in that the measuring body (1, 1') is hollow-cylindrical and has an axial cavity (10, 10); that the axial cavity (10, 10) has a cavity diameter (D1, D1'), which cavity diameter (D1, D1') is equal to a shaft diameter (DW, DW') of the shaft (W, W') to which the measuring body (1, 1') can be fastened; and that the device (V) for shafts (W, W') with different shaft diameters (DW, DW') has a plurality of measuring bodies (1, 1') with cavity diameters (D1, D1'), which cavity diameters (D1, D1') are equal to the different shaft diameters (DW, DW') of the shafts (W, W').

9. Device (V) according to one of claims 1 to 8, characterized in thatthe measuring unit (12) has a carrier unit (121) and a strain gauge (122); that the carrier unit (121) carries the strain gauge (122) on an inner circumferential surface facing radially towards the shaft (W, W'); and that the strain gauge (122) is designed to generate a measuring signal (MS) under the effect of the torque (M).

10. Device (V) according to claim 9, characterized in that the carrier unit (121) is multi-part and has a first carrier element (121a) and a second carrier element (121b); and that the two carrier elements (121a, 121b) have the shape of congruent halves of hollow cylinders.

11. Device (V) according to claim 10, characterized in that the two support elements (121a, 121b) have plug-in elements (121c); and that the plug-in elements (121c) are designed to form a detachable connection with one another by means of a positive locking.

12. A method for measuring the torque (M) of a rotating shaft (W, W'); using a device (V) with a measuring body (1, 1') and an evaluation unit (2); which measuring body (1, 1') has a measuring unit (12), a measuring amplifier unit (13), and a telemetry unit (14); wherein the measuring body (1, 1') is attached to the shaft (W, W'); wherein the shaft (W, W') is set in rotation about a longitudinal axis (A) of the shaft (W, W') and transmits the torque (M); wherein the measuring unit (12) generates a measuring signal (MS) under the effect of the torque (M); wherein the measuring amplifier unit (13) amplifies the measuring signal (MS); and wherein the telemetry unit (14) digitizes the amplified measuring signal (MS) and transmits it wirelessly to the evaluation unit (2). characterized in that a measuring body (1, 1') is provided, which measuring body (1, 1') has a main axis of inertia (X), which main axis of inertia (X) lies on the longitudinal axis (A) in the fastened state.

13. Method according to claim 12, characterized in that a measuring unit (12) is provided, which measuring unit (12) has a carrier unit (121) and a strain gauge (122), which carrier unit (121) is multi-part and has a first carrier element (121a) and a second carrier element (121b), which two carrier elements (121a, 121b) have plug-in elements (121c); and that in a first step of fastening the measuring body (1, 1') on the shaft (W, W'), the two carrier elements (121a, 121b) are placed on the shaft (W, W') and connected to one another via the plug-in elements (121).

14. Method according to claim 13, characterized in thata measuring body (1, 1') is provided, which measuring body (1, 1') has a measuring body housing (11), which measuring body housing (11) is multi-part and has a first measuring body part housing (11a) and a second measuring body part housing (11b), which two measuring body part housings (11a, 11b) have a joint unit (111), which joint unit (111) is designed to hold the two measuring body part housings (11a, 11b) together so that they can pivot about the longitudinal axis (A); and that in a second step of fastening the measuring body (1, 1') on the shaft (W, W'), the two measuring body part housings (11a, 11b) are placed in the unfolded state on the carrier unit (121).

15. Method according to claim 14, characterized in thattwo measuring body part housings (11a, 11b) are provided, which two measuring body part housings (11a, 11b) have a connecting unit (112), which connecting unit (112) is designed to detachably close the two measuring body part housings (11a, 11b) to one another; and that in a third step of fastening the measuring body (1, 1') on the shaft (W, W'), the two measuring body part housings (11a, 11b) are connected to one another by pivoting about the longitudinal axis (A) via the connecting unit (112).

Images